A liquid-phase growth apparatus and method for simultaneously growing multiple silicon carbide single crystals

Abstract

The present invention provides a liquid-phase growth apparatus and method for simultaneously growing multiple silicon carbide single crystals, belonging to the technical field of crystal growth. The apparatus includes a crucible, a seed crystal assembly, a heating assembly, a heat preservation assembly, and a temperature control assembly; the seed crystal assembly includes a seed crystal rod, a plurality of seed crystal holders symmetrically distributed along the radial direction at the lower end of the seed crystal rod, and a stirring member axially connected to the lower end of the seed crystal rod; the heating assembly is used to heat the crucible to provide a stable heat source for the growth of silicon carbide crystals; the heat preservation assembly is used to keep the crucible warm; the temperature control assembly is used to monitor and regulate the radial temperature difference of the silicon carbide seed crystal during the crystal growth process. The liquid-phase growth apparatus for silicon carbide single crystals provided by the present invention can provide sufficient carbon source for the silicon carbide crystal growth process and a radial temperature difference suitable for the growth of silicon carbide crystals, effectively improving the raw material utilization rate and crystal growth efficiency during the crystal growth process, and simultaneously growing multiple high-quality silicon carbide single crystals.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal growth, and particularly to a liquid-phase growth device and method for simultaneously growing multiple silicon carbide single crystals. Background Art

[0002] Due to its excellent physical properties such as large bandgap, high critical breakdown field strength, high saturated electron velocity, high thermal conductivity, and stable chemical properties, SiC material is considered an ideal material for preparing high-temperature, high-frequency, and high-power semiconductor devices. Among the growth methods of silicon carbide crystals, the physical vapor transport method (PVT) and the metal solvent method (liquid-phase method) both exhibit their respective characteristics and advantages. The PVT method has a relatively mature technology development and has formed a certain industrialization, but the low yield rate hinders its large-scale application. Although the liquid-phase method started relatively late, it can grow high-quality crystals under thermodynamic equilibrium during growth, effectively compensating for the deficiencies of the PVT method.

[0003] However, currently, the liquid-phase growth of SiC single crystals mainly uses a single seed crystal, resulting in low utilization rate of raw materials and low growth efficiency during the crystal growth process. During the crystal growth process, the rotation of the seed crystal is mainly relied on to accelerate the dissolution and flow of carbon elements to provide the carbon elements required for the growth of SiC crystals. However, the carbon dissolution by only relying on the rotation of the seed crystal mainly occurs near the liquid surface, and the ability to dissolve carbon elements is limited. As the growth time increases, it will lead to insufficient supply of carbon elements in the later stage of crystal growth, and a large number of defects will appear on the crystal surface. Summary of the Invention

[0004] Aiming at one or more technical problems existing in the prior art, the present invention provides a liquid-phase growth device and method for simultaneously growing multiple silicon carbide single crystals. The liquid-phase growth device for silicon carbide single crystals provided by the present invention can provide sufficient carbon source and radial temperature difference suitable for the growth of silicon carbide crystals during the crystal growth process, effectively improving the utilization rate of raw materials and the crystal growth efficiency during the crystal growth process, and simultaneously growing multiple high-quality silicon carbide single crystals.

[0005] The present invention provides a liquid-phase growth device for simultaneously growing multiple silicon carbide single crystals, including a crucible, a seed crystal assembly, a heating assembly, a heat preservation assembly, and a temperature control assembly;

[0006] The seed crystal assembly includes a seed crystal rod, a plurality of seed crystal holders symmetrically distributed along the radial direction at the lower end of the seed crystal rod, and a stirring member axially connected to the lower end of the seed crystal rod;

[0007] The heating assembly is used to heat the crucible to provide a stable heat source for the growth of silicon carbide crystals;

[0008] The heat preservation assembly is used to keep the crucible warm;

[0009] The temperature control component is used to monitor and regulate the radial temperature difference of the silicon carbide seed crystal during the crystal growth process.

[0010] Preferably, the temperature control component includes a temperature monitoring component arranged above the crucible for monitoring the radial temperature difference of the silicon carbide seed crystal and an auxiliary heating component arranged inside the crucible for regulating the radial temperature difference of the silicon carbide seed crystal.

[0011] Preferably, the temperature monitoring component is arranged at positions corresponding to the two radial ends of the silicon carbide seed crystal above the crucible.

[0012] Preferably, the heating main body part of the auxiliary heating component is located inside the stirring component.

[0013] Preferably, the crucible is provided with a detachable crucible cover, and the crucible cover is provided with a first through hole corresponding to the position and a second through hole corresponding to the positions of the two radial ends of the silicon carbide seed crystal.

[0014] Preferably, the crucible is one of a graphite crucible and an alumina crucible; and / or

[0015] The surface of the stirring component has a high-temperature resistant coating.

[0016] Preferably, the lower end of the seed crystal rod is threadedly connected to the upper end of the stirring component;

[0017] A fixing cover for fixing the heat preservation component is arranged outside the heat preservation component; and / or

[0018] The heating component includes an induction heating component.

[0019] Preferably, the heating component further includes an induction heating element located between the heat preservation component and the crucible.

[0020] The present invention also provides a liquid-phase growth method for simultaneously growing multiple silicon carbide single crystals, which is realized by the device described in the first aspect. The method includes the following steps:

[0021] S1. Place the growth raw material in the crucible and heat it until the growth raw material is completely liquefied to obtain a melt;

[0022] S2. Bring the silicon carbide seed crystal into contact with the melt and carry out crystal growth to obtain a silicon carbide single crystal.

[0023] Preferably, during the crystal growth process, the seed crystal rod rotates at a speed of 30 - 100 r / h.

[0024] The present invention has at least the following beneficial effects compared with the prior art:

[0025] At the lower end of the seed crystal rod of the present invention, a plurality of seed crystal supports are symmetrically distributed in the radial direction, enabling the growth of multiple silicon carbide single crystals in a single furnace charge. This solves the problem that the existing silicon carbide single crystal growth device can only grow one silicon carbide single crystal in a single furnace charge, resulting in low raw material utilization rate and low growth efficiency of silicon carbide single crystals, and can effectively reduce costs. In addition, the design of a plurality of symmetrically distributed seed crystal supports can ensure that the seed crystals are more stable when the seed crystal rod rotates, solving the problem that the seed crystals swing too much during the rotation of the seed crystal rod in the existing silicon carbide single crystal growth device, which easily leads to defects such as large air bubbles during the crystal growth process.

[0026] Based on the higher requirements for the fluidity of the carbon source and the melt when growing multiple silicon carbide single crystals simultaneously using multiple seed crystals, a stirring member is axially connected to the lower end of the seed crystal rod of the present invention, which can effectively promote the flow of the carbon source at the bottom of the crucible to ensure sufficient carbon source supply during the growth of multiple silicon carbide single crystals, and can effectively solve the problems of incomplete growth on the crystal surface and incomplete edges caused by insufficient carbon element supply during the crystal growth process.

[0027] Based on the problem that during the process of growing multiple silicon carbide single crystals simultaneously using multiple seed crystals, due to the expansion of the crucible size, it is easy to cause excessive changes in the temperature field between the crucible wall and the crucible center, and excessive radial temperature difference of the seed crystals, resulting in the inability to grow high-quality silicon carbide single crystals. A temperature control component is introduced into the device to monitor and regulate the radial temperature difference of the silicon carbide seed crystals in real time during the crystal growth process, so as to ensure the simultaneous growth of multiple high-quality large-size silicon carbide single crystals and meet the growth requirements of silicon carbide single crystals of different crystal forms.

[0028] The liquid-phase growth device for silicon carbide single crystals provided by the present invention can provide sufficient carbon source for the silicon carbide crystal growth process and a suitable radial temperature difference for the growth of silicon carbide crystals, effectively improving the raw material utilization rate and crystal growth efficiency during the crystal growth process, and growing multiple high-quality silicon carbide single crystals simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of a liquid-phase growth device for simultaneously growing multiple silicon carbide single crystals provided in Embodiment 1 of the present invention;

[0031] Figure 2 It is a physical diagram of two silicon carbide single crystals simultaneously grown using the liquid-phase growth device for simultaneously growing multiple silicon carbide single crystals provided in Embodiment 1 of the present invention;

[0032] Figure 3 It is a test result diagram of the rocking curves of two silicon carbide single crystals simultaneously grown by using the liquid-phase growth device capable of simultaneously growing multiple silicon carbide single crystals provided in Embodiment 1 of the present invention;

[0033] Figure 4 It is a schematic structural diagram of the liquid-phase growth device for silicon carbide single crystals used in Comparative Example 1 of the present invention;

[0034] Figure 5 It is a physical diagram of a silicon carbide single crystal grown by using the liquid-phase growth device for silicon carbide single crystals in Comparative Example 1 of the present invention;

[0035] Figure 6 It is a schematic structural diagram of the liquid-phase growth device for silicon carbide single crystals used in Comparative Example 2 of the present invention;

[0036] Figure 7 It is a physical diagram of two silicon carbide single crystals simultaneously grown by using the liquid-phase growth device for silicon carbide single crystals provided in Comparative Example 2 of the present invention;

[0037] Figure 8 It is a schematic structural diagram of the liquid-phase growth device for silicon carbide single crystals used in Comparative Example 3 of the present invention.

[0038] Reference numerals:

[0039] 1 - crucible; 2 - seed crystal assembly; 21 - seed crystal rod; 22 - seed crystal holder; 23 - stirring member; 31 - induction heating member; 32 - induction heating element; 4 - heat preservation assembly; 51 - temperature monitoring member; 52 - auxiliary heating member; 6 - fixing cover. Detailed implementation manners

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] In the description of the embodiments of the present invention, unless otherwise clearly specified and defined, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; unless otherwise specified or stated, the term "multiple groups" means two or more groups; the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. The terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device including the element. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the description of this specification, it should be understood that the orientation terms such as "upper" and "lower" described in the embodiments of the present invention are described from the angles shown in the drawings and should not be construed as limiting the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is connected "above" or "below" another element, it can not only be directly connected "above" or "below" another element, but also be indirectly connected "above" or "below" another element through an intermediate element.

[0043] As Figure 1 shown, the present invention provides a liquid-phase growth device for simultaneously growing multiple silicon carbide single crystals. The device includes a crucible 1, a seed crystal assembly 2, a heating assembly, a heat preservation assembly 4, and a temperature control assembly;

[0044] The seed crystal assembly 2 includes a seed crystal rod 21, a plurality of seed crystal holders 22 symmetrically distributed along the radial direction at the lower end of the seed crystal rod 21, and a stirring member 23 axially connected to the lower end of the seed crystal rod 21;

[0045] The heating assembly is used to heat the crucible 1 to provide a stable heat source for the growth of silicon carbide crystals;

[0046] The heat preservation assembly 4 is used to keep the crucible 1 warm;

[0047] The temperature control assembly is used to monitor and regulate the radial temperature difference of the silicon carbide seed crystal during the crystal growth process.

[0048] It should be noted that the radial temperature difference of the silicon carbide seed crystal refers to the temperature difference between one end of the silicon carbide seed crystal close to the crucible wall and one end close to the center of the crucible.

[0049] At the lower end of the seed crystal rod of the present invention, a plurality of seed crystal holders are symmetrically distributed along the radial direction, and multiple silicon carbide single crystals can be grown in a single furnace charge, solving the problem that the existing silicon carbide single crystal growth device can only grow one silicon carbide single crystal in a single furnace charge, resulting in low raw material utilization rate and low silicon carbide single crystal growth efficiency, and effectively reducing costs. In addition, the design of a plurality of symmetrically distributed seed crystal holders can ensure that the seed crystals are more stable when the seed crystal rod rotates, solving the problem that the seed crystals swing too much during the rotation of the seed crystal rod in the existing silicon carbide single crystal growth device, which easily leads to defects such as large air bubbles during the crystal growth process.

[0050] Based on the higher requirements for the fluidity of the carbon source and the melt when growing multiple silicon carbide single crystals simultaneously with multiple seed crystals, a stirring member is axially connected to the lower end of the seed crystal rod of the present invention, which can effectively promote the flow of the carbon source at the bottom of the crucible to ensure sufficient carbon source supply during the growth of multiple silicon carbide single crystals, and can effectively solve the problems of incomplete crystal surface growth and incomplete edges caused by insufficient carbon element supply during the crystal growth process.

[0051] Based on the problem that during the process of growing multiple silicon carbide single crystals simultaneously with multiple seed crystals, due to the expansion of the crucible size, the temperature field change between the crucible wall and the crucible center is too large, and the radial temperature difference of the seed crystals is too large, and high-quality silicon carbide single crystals cannot be grown, a temperature control component is introduced into the device to monitor and regulate the radial temperature difference of the silicon carbide seed crystals in real time during the crystal growth process, so as to ensure that multiple high-quality large-size silicon carbide single crystals are grown simultaneously, and the growth requirements of silicon carbide single crystals of different crystal forms can be met.

[0052] The liquid-phase growth device provided by the present invention that can grow multiple silicon carbide single crystals simultaneously can provide sufficient carbon source and suitable radial temperature difference for the silicon carbide crystal growth process, effectively improving the raw material utilization rate and crystal growth efficiency during the crystal growth process, and growing multiple high-quality silicon carbide single crystals simultaneously.

[0053] According to some preferred embodiments, the temperature control component includes a temperature monitoring member 51 disposed above the crucible 1 for monitoring the radial temperature difference of the silicon carbide seed crystal and an auxiliary heating member 52 disposed inside the crucible 1 for regulating the radial temperature difference of the silicon carbide seed crystal. The temperature detection member of the present invention is preferably an infrared temperature measurement member.

[0054] Based on the problem that during the process of simultaneously growing multiple silicon carbide single crystals with multiple seeds, the expansion of the crucible size is likely to cause excessive changes in the temperature fields of the crucible wall and the crucible center, the present invention sets a temperature monitoring component above the crucible to monitor the radial temperature difference of the silicon carbide seeds in real time and feeds back the monitoring results to the auxiliary heating component arranged inside the crucible. The auxiliary heating component adjusts the heating power to perform real-time regulation on the radial temperature difference of the silicon carbide seeds, so that the radial temperature difference of the silicon carbide seeds is within a preset range to ensure the growth of high-quality silicon carbide single crystals. The range of the radial temperature difference of the silicon carbide seeds can be adjusted according to the crystal form and size of the silicon carbide single crystal to be grown.

[0055] According to some preferred embodiments, the temperature monitoring component 51 is arranged above the crucible 1 at positions corresponding to the two radial ends of the silicon carbide seeds. It should be noted that the two radial ends respectively refer to the end of the seed close to the crucible wall and the end close to the crucible center.

[0056] The present invention arranges the temperature monitoring component above the crucible at positions corresponding to the two radial ends of the silicon carbide seeds to ensure more accurately reflecting the radial temperature difference of the silicon carbide seeds.

[0057] According to some preferred embodiments, the heating main body part of the auxiliary heating component 52 is located inside the stirring component 23. The stirring component axially connected to the lower end of the seed rod in the present invention is located in the central area of the crucible. By arranging the heating main body part of the auxiliary heating component inside the stirring component, it can be ensured that the auxiliary heating component is close to multiple silicon carbide seeds. By using one auxiliary heating component for heating, the radial temperature differences of multiple seeds can be synchronously regulated to ensure the simultaneous growth of multiple high-quality silicon carbide single crystals.

[0058] In some preferred embodiments of the present invention, the stirring component includes a stirring shaft and a plurality of stirring blades symmetrically distributed along the radial direction of the stirring shaft at the lower end of the stirring shaft. The stirring shaft has a hollow structure, and the heating main body part of the auxiliary heating component is arranged inside the hollow stirring shaft.

[0059] According to some preferred embodiments, the crucible 1 is provided with a detachable crucible cover, and the crucible cover is provided with a first through hole corresponding to the position of the seed rod 21 and a second through hole corresponding to the positions of the two radial ends of the silicon carbide seeds.

[0060] The present invention uses a crucible with a cover to prevent the crucible from dissipating heat axially too fast, which affects the temperature field distribution inside the crucible. A first through hole is arranged at the position corresponding to the seed rod on the crucible cover to facilitate the rotation of the seed rod; a second through hole is arranged at the position corresponding to the two radial ends of the silicon carbide seeds on the crucible cover to facilitate using the temperature monitoring component to monitor the radial temperature difference of the silicon carbide seeds inside the crucible in real time.

[0061] According to some preferred embodiments, the crucible 1 is one of a graphite crucible and an alumina crucible. The crucible of the present invention is mainly used to hold reaction raw materials. The types of crucibles are not limited to the above range, and different crucibles can be selected according to the crystal form of the silicon carbide single crystal to be grown and the raw materials used. When a graphite crucible is selected, it can not only be used to hold the growth raw materials but also provide a carbon source for the growth of silicon carbide crystals. When the crucible is a graphite crucible, the stirring member can effectively promote the dissolution of carbon at the bottom of the crucible, which can not only provide sufficient carbon source for crystal growth but also effectively avoid the problem that the graphite crucible near the liquid surface where carbon dissolution mainly occurs by only rotating the seed rod, resulting in the melting through of the graphite crucible.

[0062] According to some preferred embodiments, the surface of the stirring member 23 has a high-temperature resistant coating. The high-temperature resistant coating of the present invention is preferably at least one of a TaC coating and an HfC coating. The surface of the stirring member of the present invention has a high-temperature resistant coating that is insoluble in the melt of the crystal growth raw materials and does not react with the melt of the crystal growth raw materials, which can not only prevent the stirring member from being damaged but also play a role in protecting the auxiliary heating member.

[0063] According to some preferred embodiments, the lower end of the seed rod 21 is threadedly connected to the upper end of the stirring member 23. The seed rod and the stirring member of the present invention are threadedly connected, which is convenient for the installation and disassembly of the stirring member, and at the same time, the height of the stirring member from the bottom of the crucible can be controlled by the thread.

[0064] According to some preferred embodiments, a fixing cover 6 for fixing the heat preservation component 4 is arranged outside the heat preservation component 4. The present invention does not specifically limit the materials of the heat preservation component and the fixing cover. The materials of the components can be selected as heat-preserving materials, preferably graphite heat-insulating felts.

[0065] According to some preferred embodiments, the heating component includes an induction heating member 31. The present invention uses the induction heating member to heat the crucible to provide a heat source for crystal growth.

[0066] According to some preferred embodiments, the heating component further includes an induction heating element 32 located between the heat preservation component 4 and the crucible 1. The present invention uses the induction heating component to heat the crucible. Under the change of the frequency of the induction heating member, the induction heating element generates Joule heat, which provides a stable heat source for the growth of crystals through the induction heating element. At the same time, it can effectively prevent the solution from flowing out after the crucible melts through. The height of the induction heating element is greater than the height of the crucible. The axial gradient of growth can be adjusted through the height difference between the two, which is beneficial to the regulation of the temperature field in the crucible. The preparation material of the induction heating element of the present invention is preferably graphite.

[0067] The present invention also provides a liquid-phase growth method for simultaneously growing multiple silicon carbide single crystals, which is realized by the device described in the first aspect. The method includes the following steps:

[0068] S1. Place the growth raw material in a crucible and heat it until the growth raw material is completely liquefied to obtain a melt.

[0069] S2. Bring the silicon carbide seed crystal into contact with the melt and perform crystal growth to obtain a silicon carbide single crystal.

[0070] According to some preferred embodiments, during the crystal growth process, the seed crystal rod rotates at a speed of 30 - 100 r / h (for example, it can be 30 r / h, 40 r / h, 50 r / h, 60 r / h, 70 r / h, 80 r / h, 90 r / h, or 100 r / h).

[0071] To more clearly illustrate the technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with embodiments. It should be noted that the following embodiments of the present invention are only used to illustrate the technical solutions of the present invention and do not limit it.

[0072] The test methods for the performance data of the silicon carbide crystals grown in the examples and comparative examples of the present invention are as follows:

[0073] Measurement of crystal size and quality: Place the processed crystal on standard graph paper or a standard caliper to confirm the size; use an XRD diffractometer to measure the rocking curve of the crystal to determine its crystallization quality.

[0074] Example 1

[0075] As Figure 1 shown, a liquid-phase growth device for simultaneously growing multiple silicon carbide single crystals includes:

[0076] The crucible 1 is a high-purity graphite crucible, provided with a detachable crucible cover, and the crucible cover is provided with a first through hole and a second through hole; the first through hole is arranged at a position corresponding to the seed crystal rod 21, and the second through hole is arranged at positions corresponding to the radial two ends of the silicon carbide seed crystal;

[0077] The seed crystal assembly 2 includes a seed crystal rod 21, two seed crystal supports 22 symmetrically distributed along the radial direction at the lower end of the seed crystal rod 21, and a stirring member 23 threadedly connected axially to the lower end of the seed crystal rod 21; the surface of the stirring member 23 has a high-temperature resistant coating; the seed crystal rod 21 passes through the first through hole;

[0078] The heating assembly includes an induction heating member 31 located outside the heat preservation assembly 4 and an induction heating element 32 located between the heat preservation assembly 4 and the crucible, for heating the crucible to provide a stable heat source for the growth of silicon carbide crystals;

[0079] The heat preservation assembly 4 is made of a heat preservation material (graphite heat preservation felt) for heat preservation of the crucible; a fixing cover 6 for fixing the heat preservation assembly is arranged outside the heat preservation assembly 4;

[0080] The temperature control assembly includes a temperature monitoring member 51 disposed above the crucible corresponding to the position of the second through hole and an auxiliary heating member 52 with the heating main body part located inside the stirring member 23; the temperature monitoring member 51 is used to monitor the radial temperature difference of the silicon carbide seed crystal during the crystal growth process, and the auxiliary heating member 52 is used to regulate the radial temperature difference of the silicon carbide seed crystal during the crystal growth process.

[0081] Example 2

[0082] A liquid-phase growth method for simultaneously growing multiple silicon carbide single crystals, realized by the device of Example 1, includes:

[0083] S1. After assembling the device, close the furnace chamber, evacuate the furnace chamber. When the furnace chamber pressure is less than or equal to 1×10 -4 Pa, fill the furnace chamber with high-purity argon as a protective gas, place the growth raw materials in the crucible, and heat the crucible to completely liquefy the growth raw materials in the crucible to obtain a melt. Among them, the growth raw materials include Ce, Cr, and Si;

[0084] S2. Control the seed crystal rod, bring the silicon carbide seed crystal fixed on the seed crystal holder into contact with the melt, and carry out crystal growth to obtain a silicon carbide single crystal; during the crystal growth process, the seed crystal rod rotates at a speed of 80 r / h.

[0085] In this example, the physical objects of the two 4-inch silicon carbide single crystals obtained by growth are as Figure 2 shown. It can be observed that the surfaces of the two crystals are flat, the growth steps are relatively clear, and there are no macroscopic defects except for a small amount of metal droplets. The rocking curve results of the two crystals measured by the five-point method are as Figure 3 shown. Their average full width at half maximum are 38.16 arcsec and 40.32 arcsec respectively, indicating that the quality of the two crystals is relatively high.

[0086] Comparative Example 1

[0087] It is basically the same as Example 2, the difference is: using the liquid-phase growth device of silicon carbide single crystal as shown in Figure 4 shown.

[0088] The device for growing silicon carbide crystals by the traditional liquid phase method in Comparative Example 1 can only grow one silicon carbide crystal under the condition that other conditions remain unchanged. In the single-seed crystal design, when rotating at a high speed during the growth process, the swing is too large, which is likely to generate defects such as bubbles on the surface of the seed crystal, seriously affecting the crystal quality. During the crystal growth process, the main source of carbon is the dissolution of the crucible wall near the liquid surface. Only relying on the rotation of the seed crystal rod to generate flow and carbon transport, it is easy to have a shortage of carbon supply, the crystal growth time is too long, the raw material utilization rate and production efficiency are both low, and it is easy to have the phenomenon of melting through at the liquid surface of the graphite crucible. The skin effect caused by induction heating makes the temperature difference between the crucible wall and the central position of the large-size crucible large due to the large distance, and the temperature field distribution is extremely uneven in the absence of any auxiliary heat source, and the quality of the grown crystal is poor. The physical picture of the crystal is shown in Figure 5.

[0089] Comparative Example 2

[0090] Basically the same as Example 2, the difference is that: the liquid phase growth device of silicon carbide single crystal as shown in Figure 6 is adopted.

[0091] In this comparative example, a device without an auxiliary heating element is adopted. Under the condition that other conditions remain unchanged, the skin effect caused by induction heating makes the temperature difference between the crucible wall and the central position of the large-size crucible large due to the large distance, which in turn leads to a large temperature gradient at both radial ends of the silicon carbide seed crystal (the end close to the crucible wall and the end close to the central area of the crucible), the temperature field distribution is extremely uneven, and the quality of the grown crystal is poor. The physical picture of the crystal is shown in Figure 7.

[0092] Comparative Example 3

[0093] Basically the same as Example 2, the difference is that: the liquid phase growth device of silicon carbide single crystal as shown in Figure 8 is adopted.

[0094] In this comparative example, no stirring element is provided. Under the condition that other conditions remain unchanged, under the high-speed rotation of the seed crystal rod, the carbon source mainly comes from the dissolution of carbon elements at the crucible position in contact with the solution surface, and the carbon source at the bottom of the crucible cannot be fully utilized. As the crystal growth time increases, the crucible wall at the liquid surface becomes thinner and even melts through, unable to provide a carbon source for the subsequent growth of the crystal. Especially during the growth process of multi-seed crystal, the carbon element is quickly consumed, and only relying on the dissolution of carbon elements at the solution surface, the crystal growth cannot continue.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid phase growth device capable of simultaneously growing multiple silicon carbide single crystals, characterized in that: The device comprises a crucible, a seed crystal assembly, a heating assembly, a heat preservation assembly and a temperature control assembly; The seed crystal assembly comprises a seed crystal rod, a plurality of seed crystal holders arranged at the lower end of the seed crystal rod and distributed symmetrically along the radial direction, and a stirring member axially connected to the lower end of the seed crystal rod; during the crystal growth process, the seed crystal rod rotates at a speed of 30-100 r / h; The heating assembly is used to heat the crucible to provide a stable heat source for the growth of silicon carbide crystals; The heat preservation component is used to keep the crucible warm; The temperature control component is used to monitor and control the radial temperature difference of the silicon carbide seed crystal during the crystal growth process; the temperature control component includes a temperature monitoring component arranged above the crucible for monitoring the radial temperature difference of the silicon carbide seed crystal and an auxiliary heating component arranged inside the crucible for controlling the radial temperature difference of the silicon carbide seed crystal; the temperature monitoring component is arranged at a position above the crucible corresponding to the radial ends of the silicon carbide seed crystal; the heating body of the auxiliary heating component is located inside the stirring component; the surface of the stirring component has a high temperature resistant coating; The crucible is provided with a detachable crucible cover, and the crucible cover is provided with a first through hole corresponding to the position of the seed crystal rod and a second through hole corresponding to the radial two end positions of the silicon carbide seed crystal.

2. The device according to claim 1, characterized in that The crucible is one of a graphite crucible and an alumina crucible.

3. The device according to claim 1, characterized in that The lower end of the seed crystal rod is connected to the upper end of the stirring member through a thread; A fixing cover for fixing the heat preservation component is arranged outside the heat preservation component; and / or The heating assembly includes an induction heater.

4. The device according to claim 3, characterized in that The heating component also includes an induction heating element located between the heat-insulating component and the crucible.

5. A liquid phase growth method for simultaneously growing multiple silicon carbide single crystals, characterized in that: The method is implemented by the device according to any one of claims 1 to 4, and comprises the following steps: S1. placing the growth material in a crucible and heating the growth material until it is completely liquefied to obtain a melt; S2. contacting the silicon carbide seed crystal with the melt to perform crystal growth to obtain a silicon carbide single crystal.

Images